In an optical communication between stations, an optical module for optical amplification amplifies an optical signal in order to amplify a maximum output of the optical signal, For example, Japanese Patent Application Publications No. 2005-244305 (hereinafter referred to as Document 1) and No. 2010-279956 (hereinafter referred to as Document 2) disclose a countermeasure against an erroneous light emission.
However, Document 1 and Document 2 lack in safety measure during canceling an light emission.